Johnson was greeted with laughter at the start of PMQs as he told MPs it was a “big day” for the government, but insisted he intended to “keep going” as he had a “colossal mandate”.
Starmer said any ministers resigning now after having long defended Johnson did not have a “shred of integrity”.
“Isn’t this the first recorded case of the sinking ships fleeing the rat?” the Labour leader said.
Starmer added of those ministers who had not yet quit: “As for those who are left, only in office because no-one else is prepared to debase themselves any longer.
“The charge of the lightweight brigade. Have some self-respect.”
“Doesn’t the country deserve better than a z list cast of nodding dogs?”
So far 17 ministers and junior ministerial aides have so far announced their resignations. One minister resigned just minutes into the start of PMQs.
The demands for Johnson to go are coming from across all wings of the party.
Formally super loyal backbenchers Lee Anderson and Tom Hunt, from the 2019 intake, have called on Johnson to quit.
Robert Halfon, the well respected chair of the Commons education committee, called for a change of leader given the “real loss of integrity” but also a “failure of policy”.
Johnson is seen as unlikely to resign, but he could face another vote of no confidence if the 1922 committee of backbench MPs decides to change its rules, allowing a second vote within a year.